I now can sort of confirm the issue, however here it is slightly different, marked in blue.

- open sketch or create new one with some geometry
- box select all or part of the sketch
- Sketch->Sketcher tools->Delete All Geometry. Note: FreeCAD is still alive
- close Sketcher: now FreeCAD crashes.

I now can sort of confirm the issue, however here it is slightly different, marked in blue.

- open sketch or create new one with some geometry
- box select all or part of the sketch
- Sketch->Sketcher tools->Delete All Geometry. Note: FreeCAD is still alive
- close Sketcher: now FreeCAD crashes.

I can reproduce it. It is really weird, the debugger stops at different places on different executions... tomorrow with more time...

I now can sort of confirm the issue, however here it is slightly different, marked in blue.

- open sketch or create new one with some geometry
- box select all or part of the sketch
- Sketch->Sketcher tools->Delete All Geometry. Note: FreeCAD is still alive
- close Sketcher: now FreeCAD crashes.

I can reproduce it. It is really weird, the debugger stops at different places on different executions... tomorrow with more time...

With the second attempt I got this callstack and this looks as it's the real reason: